THE area to be discussed is on the Central Plateau and part of the coastal Bay of Plenty, and is of approximately 9520 km’. Some 3 000 farmers are carrying approximately 300 000 dairy cows, 2 000 000 sheep, 300 000 beef cattle and 10 000 deer, and there is a marked move towards diversification, particularly into kiwifruit growing and other subtropical fruits on the coastal strip.
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(55 KB)Field monitoring of black beetle, Heteronychus arutor (F.), populations in Waikato pasture showed a strong association between black beetle numbers and the presence of Paspalum dilatatum Poir. Increasing paspalum gave higher adult numbers in spring resulting from increased overwintering survival, and in some seasons, reduced autumn dispersal. Numbers of larvae damaging pasture in February were directly related to adult numbers in September. Black beetle preferentially select paspalum plants in mixed pasture. This can place paspalum at a competitive disadvantage relative to other pasture species, but also permits the retention of higher adult black beetle numbers, even at low paspalum levels.
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(167 KB)The annual pattern of pasture growth rates on two Rangitaiki plains dairy farms is examined. The cyclical pattern of growth is largely determined by temperature, moisture and light levels, but modified by changes in the relative importance of individual pasture species through the year. Within this pattern, variation from year to year is least during the spring, apparently related to the flowering period of ryegrasses, and greatest in the summer-autumn period. Animal production systems are often constrained by shortfalls in late winter-early spring feed supplies and the variability of summerautumn growth. Grazing management has a limited potential for directly modifying the pattern of pasture growth. However, application of nitrogen fertilizer can increase late winter growth rates to help overcome feed deficits, while the use of specialized pastures can ensure more reliable summer growth.
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(112 KB)The satisfactory establishment of white clover in redevelopment areas already colonized by Rhizobium trifolii depends upon (a) the effectiveness of the naturalized population, (b) the ability to introduce more effective strains, and (c) the persistence of introduced strains in a competitive situation. The effectiveness of naturalized populations of R. trifolii isolated from pasture soils on the Central Plateau is inferior when compared under standard conditions with strains used for inoculation of white clover. However, the superior competitive ability of naturalized populations prevents the satisfactory introduction of inoculant strains using conventional inoculation techniques. Alternative inoculation methods have been used to increase the proportion of nodules formed from the inoculant strain. Techniques are now being sought to improve the persistence of introduced strains of R. trifolii in competitive situations.
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(95 KB)In a P-year Wairau lucerne trial, plots were grazed on a 3- or 6- weekly rotation; Half of each plot was hard grazed in June to control overwintering aphids. In the second year a spring/autumn spraying was applied. June grazing reduced aphid populations in spring from 37 to 3 per stem, and gave no significant difference in dry matter yield. Three-weekly spelling, although reducing aphid numbers, halved plant populations and root weight and markedly decreased dry matter yield. In the second year, 6-weekly spelling yielded 13 120 kg/ha, and 3-weekly only 3 540 kg/ha. Spraying of aphids increased yields, but not significantly. The results show that cheap methods of controlling aphids in lucerne can be developed using grazing management.
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(105 KB)Increasing amounts (0, 0.25, 0.50, 0.75 and 1.0 kg DM/ewe/day) of chopped (10 cm) wilted silage (32.5% DM) was offered to groups of oestrous-synchronized mixed-age Coopworth ewes (n = 50/ group), grazing two restricted levels of autumn pasture (0.8 and 1.6 kg DM allowance/ewe/day). Gains over the 48-day trial .increased linearly with the amount of silage fed from -140 to 68 and from -65 to 105 g/ewe/day, respectively, at each allowance. Ovulation rates were measured by laparoscopy at two oestrous cycles. A linear model with logit transformation was used to determine treatment effects on the proportion of multiple ovulations. At both cycles there was a linear effect between multiple ovulations and level of silage intake and thereby sustained gain. Fine-chopped wilted silage proved superior to conventional silage for flushing.
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(121 KB)Limitations that were experienced with Jucerne/Tama are discussed chiefly in a dryland context. With irrigation, the addition of Matua prairie grass, ‘Grasslands G14’ phalaris, and Nui ryegrass with white clover to the lucerne/Tama system enabled less reliance to be placed on hay feeding in winter. End-of-September lambing in an attempt to achieve better matching of feed supply and demand has proven to be unsatisfactory for lamb finishing in dominantly lucerne systems. Change to greater content of perennial grass should enable earlier lambing at beginning of September, even at a high stocking rate (22 ewes/ha), and this is currently being researched. Improved lamb performance is also desired.
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(152 KB)THE farm I am about to describe has just completed 50 years of factory supply seasonal dairying. About one-third of the dairy farms in the district are owner operated by people who have bought land settled by their forebears 50 to 70 years ago - that generation of pioneers also established the Rangitaiki Plains Dairy Company, which has grown into a large and efficient manufacturer of milk products for local and world markets. The district used to be known as the Rangitaiki swamp. Because we are only 2 or 3 m above sea level, farm and district drainage systems are essential to take surplus water to the sea 7 km away. We are blessed with generous sunshine (1800 to 2000 h/yr) and rainfall (1400 mm/yr) . Frosts (approximately 40 per year) have occasionally been recorded in December, and in most other months. Sir Bruce Levy once called this the best grass-growing district in the world. FARM
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(56 KB)In the drought-prone district of Broadlands a system of dairying on lucerne has evolved. The history of such a farm from 1966 to 1979 is described. From 1970, farm area has increased by 70%, luceme area by 400%, cow numbers by 108%, and milkfat production by 312%. Seasonal farm management is described, including bloat control, fertilizer. treatments, and harvesting or growing of supplementary feeds. Comment is made that this farming system offers considerable scope for expansion of dairy production in the district.
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(62 KB)The reasons for the large changes in pumice land farming systems over the last 10 years are outlined and the resultant increases in production presented. The large increases in district milkfat production and milkfat per cow are attributed to management changes such as later calving, shorter lactation, winter management, and the grazing of lucerne. Changes in sheep farm management such as later lambing, earlier weaning, grazing of lucerne, the use of rotational grazing, and a decline in beef cattle are outlined. Lambing percentages have increased, but wool weights are static. Future management changes that farmers should follow are outlined.
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(212 KB)The perennial ryegrass cultivars ‘Grasslands Ruanui’, ‘Grasslands Ariki’ and ‘Grasslands Nui’ were sown with clover and compared at three levels of irrigation under rotational grazing with sheep. Ryegrass cultivar had little effect on total annual pasture production, although Nui pastures produced more total DM in autumn and winter. Nui was the most persistent cultivar and produced substantially more ryegrass than the orhers (6.1 t/ha, compared with 4.1 t/ha for Ruanui and 3.3 t/ha for Ariki) . Nui pastures produced less white clover, volunteer grasses and weeds. When grazed at the same stocking rate, sheep liveweight gain was similar regardless of ryegrass cultivar.
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(112 KB)The response of hill pastures to N fertilizer was measured at Ballantrae, the Grasslands Division, DSIR, hill country research station. Both initial and residual responses were affected by the timing and rate of nitrogen fertilizer applications. The pasture response at lower rates of N varied between 10 and 25 kg DM/kg N, while at higher rates the efficiency of N use was reduced to 5 to 7 kg DM/kg N. Most efficient use of nitrogen occurred on cool aspects. An analysis of the profitability of using fertilizer N to intensify hill country sheep farming suggests that fertilizer N may be useful where additional animals can be carried, by providing nitrogen-boosted pasture for a limited period over the winter/spring months.
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(110 KB)The production of milk and milk components by identical twin cows given ad libitum access to swards of Nui or Ruanui perennial ryegrasses, or a tetraploid hybrid ryegrass (G4708), for short-term periods in spring, summer, and autumn, showed no consistent differences. Similar trials conducted in the spring with unrelated cows grazing Tama tetraploid Westerworlds ryegrass or a tetraploid Italian ryegrass (G4709) also showed no production differences. The use of these cultivars in dairy production systems is therefore more likely to be determined by such agronomic features as annual and seasonal yields, disease resistance and persistency rather than nutritional characteristics.
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(108 KB)The Tikitere forest farming research area was established in 1973 to determine the feasibility of integrating farming and forestry. This paper reports on progress in evaluating the effects of tree density and spatial arrangement on numbers and performance of livestock, and availability and productivity of pasture. Only 5 years after planting Pinus radiata (D. Don) into pasture there were large reductions in carrying capacity with increasing tree density, and it is apparent that a tree management regime leading to a final crop of 400 sph is unsuitable for combining with intensive livestock production. Individual livestock performance as measured by both liveweight change and wool production was poorer under trees, and a number of possible explanations are given, Availability of pasture for livestock was affected both by a reduction in dry matter production with increasing tree density and by the covering of ground with thinning and pruning debris. The effects of the latter on managing livestock under trees are discussed.
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(94 KB)Dry matter production data for pure lucerne, overdrilled lucerne and pasture are presented for 14 sites on pumice soils. On average, the annual dry matter yield of lucerne, harvested at early basal shoot movement, was 50% higher than from pasture, ranging from 128% higher on a drought-prone soil where the pasture was dominant browntop to 33% on a more moisture-retentive soil type where the pasture was ryegrass dominant. From April until late October there was little difference in total dry matter between lucerne and pasture, although pasture had a .more even distribution of usable production than lucerne ‘managed for maximum yield. Attempts to fill the winter/spring gap in lucerne production through introducing grasses and cereals have met with variable success. It is suggested that, on the more moisture-retentive soils, pasture production could be improved through grazing management and the use of more drought-resistant cultivars. Such an approach may meet the feed demands of animals more closely than an increasing dependence on lucerne with its specific management requirements.
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(134 KB)An outline is given of the development and problems of a Crownballoted farm since settlement 12 years ago. Its physical characteristics and limitations are indicated, stocking policy and performance to date are outlined. Supplementary feeding systems for summer and winter requirements of stock are examined as a process to development of new pastures and lucerne. Problems with the persistence of perennial ryegrass pastures are also discussed. A large plot trial comparison of some major perennial ryegrass cultivars has been established in a new grass paddock under grazing, and some measurements and observations recorded. Performance of the standard Ruanui ryegrass was notably inferior to other strains of ryegrass. The importance of adequate subdivision is recognized and an outline is given of the various types of fencing systems, including electric. Advantages and problems of sheep farming in the pumice country are documented, as well as the management methods evolved to minimize the disadvantages to allow continued good stock and farm production.
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(71 KB)Energy considerations, together with the removal of the U.K. Government’s subsidy on nitrogen fertilizer, have not shifted farmer emphasis from heavy reliance on bag nitrogen. ADAS officials are still convinced that bag nitrogen rather than legume nitrogen is the answer to increased production, even though U.K. farmers are now applying nitrogen at 20 times their pre-war rates for a mere doubling of stock numbers over this period. Examples are given of farmers from different regions in Britain who are successfully basing their enterprises on legumes rather than fertilizer nitrogen, Problems of herbage legume seed multiplication are discussed, along with the prejudice legumes suffer in terms of unpredictability, persistence, disease susceptibility, bloat and oestrogenicity. There is clear need for a large research effort to be mounted in terms of biological nitrogen fixation in the U.K. The relevance to New Zealand agriculture-of a projected move of U.K. farmers away from fertilizer nitrogen is discussed in the light of the proposed Kapuni urea factory.
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(107 KB)Small plot mowing trials carried out on central North Island pumice soils have shown that Huia white clover and SI70 tall fescue support high grass grub populations, while the resistant legumes Wairau lucerne and Maku Lotus pedunculayus suppress grass grub numbers to low levels. Measurement of the effects of grass grub on herbage production has highlighted both the susceptibility of white clover, Nui and Ruanui ryegrasses, and browntop to grass grub attack, and the potential of highly productive resistant or tolerant specres (lucerne, tall fescue and to a lesser extent Apanui cocksfoot and Matua prairie grass) for lessening the impact of grass grub on pasture production in this region.
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(159 KB)Legume-based pastures of perennial ryegrass (‘Grasslands Ruanui + Nui’) and ‘Grasslands Roa’ tall fescue were established on semideveloped peat soils near Hamilton in autumn 1975. Pastures were grazed with yearling Friesian steers at equal stocking rates from August until March during the years 1976 to 1979. Roa tall fescue swards substantially outyielded those of perennial ryegrass in January, February and March with an overall total yield advantage of some 21%. As a result, in most months, steers grazing Roa were offered approximately 15% more DM, which was utilized with similar efficiency to ryegrass (67% tall fescue and 69% ryegrass). Steer liveweight gains per head and per hectare were 10% higher on Roa tall fescue pastures, with average daily growth rates being 0.74 kg/head and the 3-year mean total LWG/ha being 970 kg from the tall fescue pasture.
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(139 KB)Three trials in the Waikato and Northland examined the effects of applying a range of grazing pressures at various times of the year on mixed pastures of ryegrass (Lolium perenne), paspalum (Paspalum dilatafum), and white clover (Trifolium repens). The effect of lax grazing or hay and silage making in spring was to reduce paspalum content in the immediate following summer, with an associated increase in ryegrass content. These effects persisted for at least 12 months. Lax grazing with sheep in each season increased paspalum content. Lax summer grazing with she&p and very hard summer grazing with cattle increased paspalum and decreased ryegrass content. The latter effect was thought to be due to pulling of ryegrass. Some practical aspects of the results are discussed
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(93 KB)AMV was shown to be transmitted by sap, aphids and through lucerne seed, but not by Cuscuta. Virus source and test plant influenced transmission frequency. Sap-inoculation tests showed that 20 species of plants were susceptible to this virus. Thirteen species of plants from the fields where AMV had been detected were tested but only three were found to be infected with the virus.
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